DE102022108943A1 - Method and system for controlling a gear change in response to a change in driving mode - Google Patents

Abstract

In one aspect, a method for controlling a gear shift in response to a driving mode change includes: determining a maximum number of allowable low gear shift stages according to a result of determining a state of a transmission, calculating an immediately post-gear shift expected speed of a turbine wheel for each in the maximum number of allowable lower gear shift stages included, using a current speed of an output shaft of the transmission and a gear ratio of each stage and comparing the calculated expected speed of the turbine wheel with a preset allowable speed of the same for each stage, setting the lowest gear shift stage from gear shift stages at which the expected rotation speed of the turbine wheel and the allowable rotation speed thereof satisfy a predetermined condition as a target gear shift stage, and execute gear shift control to obtain an actual Ga ng shift stage down to the target gear shift stage.

Description

Cross reference to related application

The present application claims priority from Korean Patent Application No. 10-2021-0047283 , filed on April 12, 2021, the entire contents of which are incorporated herein by this reference for all purposes.

background

Area

The present disclosure relates to a method and system for controlling gear shifting in response to a change in driving mode, and more particularly to a method and system for controlling gear shifting in response to a change in driving mode, the method and system being capable of: to control the gear change in a case where switching from an operation mode (e.g. an ECO mode, a normal mode, a comfort mode or the like) other than a sport mode to the sport mode takes place during driving, and wherein an automatic transmission vehicle that System for controlling the gear change in response to a change in driving mode.

background

Typically, an automatic transmission is a mechanical device capable of automatically obtaining an optimum torque conversion result according to a running speed of a vehicle and a load. The automatic transmission is set up so that gears are shifted by operating a gear shift solenoid and a clutch under the control of a transmission control unit (TCU) that issues a gear shift control command at the request of a driver or based on a driving condition of the vehicle.

The transmission control unit (TCU), which controls the automatic transmission, receives information about a condition of the vehicle from an engine control unit (ECU) and issues a control command to control the gear shift solenoid and the clutch to perform the gear change based on of the information received. In addition, the transmission control unit issues a request to the engine control unit for a change in output at a timing for a gear change according to operations of the gear shift solenoid and the clutch.

For example, when the driver presses an accelerator pedal to accelerate the vehicle, the transmission control unit requests the engine control unit to reduce the engine torque in order to perform a smooth upshift or downshift gear shift. Then, an engine torque increase request is issued to the engine control unit after the engine torque decrease request is issued to synchronize a rotational speed of an input shaft of the automatic transmission and a rotational speed of an output shaft of a motor.

The gear shift control unit also determines an optimal gear shift stage suitable for an amount of work on an accelerator pedal and a speed of the running vehicle, using a gear shift pattern (a gear shift map) calculated from a relationship between the amount of work on an accelerator pedal and a Output speed of the transmission, ie a vehicle speed is set. Then, the optimal gear shift stage is set as a target gear shift stage, and a target hydraulic pressure (solenoid work value) for gear shifting to the target gear shift stage is determined. The shift solenoid is controlled based on the target hydraulic pressure.

The automatic transmission vehicle that satisfies predetermined specifications has a function of selecting a driving mode. The drive can select a desired drive mode via a dedicated switch mounted at a convenient location within the vehicle and operable to select a drive mode. When the driving mode is selected, a gear shift pattern matching the selected driving mode is retrieved, and gear shifting is accordingly performed in accordance with the gear shift pattern. Thus, increased responsiveness of the vehicle and different shift feel can be obtained according to the driver's preference.

Typically, depending on the vehicle type, selectable driving modes include an ECO mode, a normal mode, a comfort mode, a sport mode, and the like. Among these modes, the sport mode is a mode in which a gear change reference point is set to be at a higher speed than the other modes. Gear shifting to a high stage occurs at the expense of fuel efficiency in a state where the vehicle gains sufficient driving power. In this way, the driver can enjoy a more dynamic driving style and feel greater vehicle responsiveness.

However, when the driving mode is changed to the sport mode while driving, the gear shifting is performed smoothly in accordance with a gear shift reference point set to be in the gear shift pattern assigned to the sport mode (a gear shift map assigned to the sport mode, which has the following influencing factors: a vehicle speed and an amount of work on a pedal.

The foregoing is only intended as an aid in understanding the background of the present disclosure and is not intended to imply that the present disclosure falls within the scope of related art that is already known to those skilled in the art.

short version

In one aspect, there is now provided a method and system for controlling a gear change in response to a change in driving mode, the method and system being able to perform a downshift by setting a target gear shift stage to a low stage, which is lower than a gear shift stage set to be a gear shift pattern (a gear shift map) associated with a sport mode when a change from a driving mode other than a sport mode to the sport mode occurs during driving. A driver's desire to enjoy dynamic driving can be satisfied.

In one aspect, there is provided a method for controlling a gear change in response to a change in driving mode, the method comprising: (a) determining a maximum number of allowable low gear shift stages according to a result of determining a state of a transmission based on information about an accelerator pedal operation (an accelerator pedal position sensor (APS) signal) when a request to change a driving mode to a sport mode is detected during driving, (b) calculating an immediately after gear change expected rotation speed of a turbine wheel for each stage that is in the maximum number of allowable low gear shift stages is included, using a current rotational speed of an output shaft of the transmission and a gear ratio of each stage, and comparing the calculated expected rotational speed of the turbine wheel (a rotational speed of an input shaft of the transmission) with a previous one set allowable turbine speed for each step, (c) setting the lowest gear shift step from gear shift steps at which the expected turbine speed and the allowable turbine speed meet a predetermined condition such that they have a target gear shift step within the maximum number of allowable is low gear shift stages, and (d) executing a gear shift control to downshift a current gear shift stage to the target gear shift stage.

Here, the “expected rotation speed of the turbine” means a value obtained by taking the rotation speed of the input shaft of the transmission directly connected to the turbine as an anticipated rotation speed value of a torque converter turbine arranged between an engine and a transmission. This value can be derived from a simple equation in which the actual rotational speed of the output shaft of the transmission (a vehicle speed) is multiplied by the reciprocal of a gear ratio of the target gear shift stage.

The term “allowable turbine wheel speed”, one of the terms used to describe an embodiment of the present disclosure, means an allowable speed of the input shaft of the transmission. The allowable rotation speed of the turbine wheel means a maximum value of a rotation speed of the input shaft of the transmission at which the driving force of an engine can be stably output by gear shifting without sacrificing a load capacity at each gear shift stage. The allowable rotation speed of the turbine wheel is a fixed value to be set in a recording device such as a memory so as to change with the gear shift stage (because a gear ratio changes with the gear shift stage).

In a preferred aspect, in (a) determining the maximum number of allowable low gear shift steps, if an output signal of an APS is at or above a set value at a time when the request to change the driving mode is detected, it can be determined that the transmission is in an on state and then, if the output of the APS is below the set value, it is determined that the transmission is in an off state.

In a preferred aspect, when the transmission is in the engaged state, the number of low gear ratios lower than a set gear ratio determined via a gear shift pattern associated with a sport mode can be determined as the maximum number of low gear ratios allowed, and then , when the transmission is in the off state, the maximum number of allowable low gear shift steps is determined as 1 such that low-level gearshifting is permitted only to a low gearshift level (a set gearshift number minus 1) that is one level lower than the set gearshift level determined via the gearshift pattern associated with the sport mode.

In a further preferred aspect, in the method, at (b) the calculation of the expected immediately after the gear change speed of the turbine wheel, the expected speed of the turbine wheel immediately after the gear change for each stage to a value (the current speed of the output shaft of the transmission / the gear ratio of each stage) which results from dividing the current speed of the output shaft of the gearbox by the transmission ratio of each stage.

In a further preferred aspect, in the method at (c) setting the lowest gear shift ratio, the predetermined condition may be that the expected speed of the turbine wheel does not exceed the permissible speed of the turbine wheel.

In certain preferred aspects, the method may further include: (e) comparing the time (a gearshift control time) required for the gearshift controller to downshift the current gearshift stage to the target gearshift stage at (d) the execution of the gearshift control with a preset setting gear shift timing.

In preferred aspects, in the method, when the gearshift timing exceeds the set gearshift timing, a process in such a state can be terminated without further executing the gearshift control, and can then be determined when the gearshift timing is shorter than the set gearshift timing whether the gear change to the target gear shift stage is completed or not, and if the gear change is completed within the set gear shift timing, the process can be ended.

In preferred aspects, in the method, in a case where the gearshift timing is shorter than the set gearshift timing and the gear change to the target gearshift stage is not completed, the return to (d) the execution of the gearshift control and (d) the execution of the gear shift control, and (e) comparing the time required for the gear shift control are repeatedly performed.

In certain preferred aspects, the method may further include: (f) executing control to restrict gear shifting toward a high gear shift stage after gear shifting to the target gear shift stage is completed.

In certain preferred aspects, in the method (f), executing the gear shift restriction control comprises: (f-1) making a gear shift prohibition request to the high gear shift stage to restrict the gear shift to the high gear shift stage after the gear shifting to the target gear shifting is completed, and (f-2) comparing the current gear shift stage (a gear shift stage corresponding to the target gear shift stage) with a set gear shift stage determined via a gear shift pattern associated with a sport mode, according to a current output signal of the APS and a current vehicle speed, and determining, depending on a result of the comparison, whether prohibition of gear shifting to the high gear shift stage is released or maintained.

In certain preferred aspects, in the method (f-2), comparing the current gear shift stage with the setting gear stage may include: (f-2-1) immediately releasing the prohibition of gear shifting to the high gear stage because the control for prohibiting the gearshifting to the high gearshift stage is unnecessary when the current gearshift stage (the gearshift stage corresponding to the target gearshift stage) is equal to the setting gearshift stage or is the high gearshift stage, and (f-2-2) maintaining the prohibition of gearshifting to the high gearshift stage when the current gearshift stage (the gearshift stage corresponding to the target gearshift stage) is a lower gearshift stage than the setting gearshift stage, and determining a timing at which the prohibition of gearshifting to the high gearshift stage is released by using additional information .

In certain preferred aspects, the method in (f-2-2) maintaining the prohibition of gear shifting may compare a current engine speed with a preset allowable engine speed to prevent engine overrun; then, if the current engine speed is higher than the permissible engine speed, a forced gear shift to a high gear ratio, which is one step higher than the current gear ratio, can be performed and then the resulting high gear ratio can be compared with the setting gear ratio, the via the gear shift pattern assigned to the sport mode according to the current output signal the APS and the current vehicle speed is determined; and when the high gear stage which is one stage higher is higher than the set gear stage, the prohibition of gear shifting to the high gear stage can be released.

In certain preferred aspects, the method at (f-2-2) of maintaining the prohibition of gear shifting when the current engine speed is lower than the allowable engine speed based on an output signal of the APS and the time over which its output signal is further provided, determining whether or not a driver intends to experience acceleration, wherein if the output signal of the APS is further provided in a state of being at or above the set value for a set time or longer , it can be determined that the driver actually intends to experience acceleration so that a timer can be operated and at the same time an increase in vehicle speed obtained after a point in time when gear shifting to the current gear stage is completed, with a preset reference value for the increase in vehicle speed speed can be compared, and when the increase in vehicle speed is at or above the vehicle speed increase reference value, this situation can be recognized as an increase in vehicle speed due to a downgrade of a road and not as an intention to experience acceleration , and thus the forced gear shifting to a high gear stage which is one stage higher than the current gear stage can be performed immediately, and thereafter the resulting high gear stage can be compared with the setting gear stage corresponding to the gear shift pattern assigned to the sport mode the current output signal of the APS and the current vehicle speed, and when the high gear shift step which is one step higher is higher than the set gear shift step, the prohibition of gear shifting to the high gear shift step can be released.

In certain preferred aspects, in the method, as a result of comparing the vehicle speed increase obtained after the time gear shifting is completed with the vehicle speed increase reference value, when the vehicle speed increase is below the reference value for the increase in vehicle speed, a value of the time for which the timer is operated is compared with a preset time reference value, and at a point in time when the time value is higher than the time reference value, the forced gear shift to a high gear shift stage, which is one step higher than the current gearshift step, and then the resulting high gearshift step can be compared with the set gearshift step that is determined by the gearshift pattern assigned to the sport mode according to the current output signal of the APS and the current vehicle speed speed is determined, and when the high gear shift stage which is one stage higher is higher than the setting gear stage, the prohibition of gear shifting to the high gear stage can be released.

In certain preferred aspects, in the method, the forced gearshifting to a high gearshift stage that is one stage higher than the current gearshift stage (the gearshift stage that corresponds to the target gearshift stage) can be performed, and then the resulting high gearshift stage can be adjusted with the setting - gear shift step are compared, which is determined via the gear shift pattern assigned to the sport mode according to the current output signal of the APS and the current vehicle speed; as a result of the comparison, when the high gear shift stage which is one stage higher is lower than the setting gear stage, the forced gear shifting to a high gear stage which is one stage higher can be performed; and thereafter, returning to comparing the resultant high gearshift stage with the setting gearshift stage, and comparing the resultant high gearshift stage and a subsequent operation may be repeatedly performed.

One or more of the foregoing steps may be performed using a processor or controller.

According to another aspect of the present disclosure, there is provided a system for controlling a gear change in response to a change in driving mode, the system comprising: a mode change switch for changing a driving mode, an accelerator position sensor (APS), configured to detect a driver's operation of an accelerator pedal and output a corresponding signal, a vehicle speed detector configured to detect a rotational speed of an output shaft of a transmission, and a transmission control unit (TCU )), which is set up to control the transmission based on information received from the mode change switch, the APS and the vehicle speed capability detector are provided, wherein when a change from a driving mode other than a sport mode to the sport mode is detected during driving, the transmission control unit executes a downshift control to a low gearshift stage, which is one stage lower than a setting gearshift stage, the is determined via a gear shift pattern assigned to the sport mode.

In certain preferred aspects, in the system, the transmission control unit may include: a gear shift mode change detection unit configured to receive information about a driving mode change from the mode change switch and retrieve a gear shift pattern that matches a driving mode to which a change is taking place, a unit for Determination of a number of low gear shift stages, which is arranged to determine a maximum number of allowable low gear shift stages according to a result of determining a state of the transmission based on information about an accelerator pedal operation (a signal of an APS) when the gear shift mode change detection unit determines the change of the driving mode to the sport mode while driving, an expected rotation speed of a turbine calculation unit arranged to calculate an expected rotation speed e calculates a turbine wheel (a rotational speed of an input shaft of the transmission) for each stage included in the maximum number of allowable low gearshift stages using a current rotational speed of an output shaft of the transmission and a gear ratio of each stage, a target gearshift stage determination unit so configured that they select the lowest gear shift stage from gear shift stages at which the calculated expected turbine wheel speed for each stage contained within the maximum number of allowable low gear shift stages and a preset allowable turbine wheel speed for each stage meet a predetermined condition as a target sets gear shift stage, and a transmission controller configured to execute gear shift control to downshift a gear shift stage to the target gear shift stage.

In certain preferred aspects of the system, if an output signal of the APS is at or above a set value at a time when a drive mode change request is detected, the unit for determining the number of low gear shift steps may determine that the transmission is in an engaged state and may determine as the maximum number of allowable low gear ratios the number of low gear ratios lower than the setting gear ratio determined by the gear shift pattern assigned to the sport mode, and then when the output signal of the APS is below the set value, the unit for determining the number of low gear shifts determines that the transmission is in an off state and can determine the maximum number of allowable low gear shifts as 1, such that a low gear shift only into a low gear shift ( a e set gearshift step number minus 1) is allowed, which is one step lower than the set gearshift step determined via the gearshift pattern assigned to the sport mode.

In certain preferred aspects, in the system, the expected turbine speed calculation unit may calculate the expected turbine speed immediately after the gear change for each stage by dividing the current speed of the output shaft of the transmission detected by the vehicle speed detector by the gear ratio of each Calculate stage (the current speed of the output shaft of the gearbox/gear ratio of each stage).

In certain preferred aspects, in the system, the predetermined condition may be a condition that the expected speed of the turbine wheel does not exceed the allowable speed of the turbine wheel.

In certain preferred aspects, in the system, the transmission control unit may further include a timing comparison unit configured to count the time (a gearshift timing) required for the gearshift controller to downshift a current gearshift stage to the target gearshift stage and the counted one Compare gear shift timing with a preset set gear shift timing, wherein when the gear shift timing exceeds the set gear shift timing, the timing comparison unit can make a request to the transmission controller to prevent the gear shift control.

In certain preferred aspects, in the system, the transmission control unit may include a gearshift prohibition request unit configured to make a request to the transmission controller to prohibit gearshifting to a high gearshift stage to restrict gearshifting to the high gearshift stage after the gearshifting in the target gear shift stage is completed.

According to an embodiment of the present disclosure, when switching from a driving mode other than the sport mode to the sport mode occurs during driving, the target gear shift stage is set to a stage lower than the gear shift stage set to be in the gear shift pattern (gear shift map) associated with the sport mode (gear shifting up to the lowest gear shift stage is permitted based on the allowable speed of the turbine wheel for each stage). Thus, the driver can enjoy dynamic driving.

Other aspects are disclosed below.

character list

• 1 eine schematische Ansicht, in der eine Ausführung eines Fahrzeugs mit Automatikgetriebe veranschaulicht ist, das ein Gangschaltsteuersystem aufweist, das auf eine Änderung eines Fahrmodus gemäß einer Ausführungsform der vorliegenden Offenbarung anspricht,
• 2 eine Tabelle, in der ein Vorgang des Einstellens einer Soll-Gangschaltstufe dargestellt ist,
• 3 ein Ablaufdiagramm, in dem sequentiell Gangschaltsteuerprozesse in einer Abfolge veranschaulicht sind, die von dem Gangschaltsteuersystem in 1 durchgeführt werden, und
• 4 ein Ablaufdiagramm zur Steuerung zur Verhinderung eines Hochschaltens auf eine hohe Gangschaltstufe, wobei die Steuerung unmittelbar nach der Durchführung des Herunterschaltens als Reaktion auf eine Änderung des Fahrmodus in einen Sportmodus während des Fahrens durchgeführt wird.

The above and other objects, features and other advantages of the present disclosure will be better understood from the following detailed description when taken in connection with the accompanying drawings; show in it:

• 1 12 is a schematic view illustrating an embodiment of an automatic transmission vehicle having a gear shift control system responsive to a change in a driving mode according to an embodiment of the present disclosure.
• 2 a table showing a process of setting a target gear shift stage,
• 3 FIG. 14 is a flowchart sequentially illustrating gear shift control processes in a sequence executed by the gear shift control system in FIG 1 be carried out, and
• 4 FIG. 14 is a flowchart for high-speed upshift prevention control, the control being performed immediately after the downshift is performed in response to the driving mode being changed to a sport mode during driving.

Detailed description

A preferred embodiment of the present disclosure will be described in detail below with reference to the drawings.

The terms used throughout this specification are for the purpose of describing the preferred embodiment only and are not intended to limit the present disclosure in any way. A singular noun has the same meaning as when it is used in the plural, unless it has a different meaning in the context.

Additionally, as used herein, the term "comprising," "having," or the like is intended to indicate that a feature, number, step, operation, ingredient, component, or combination thereof described in the specification is available. It should be understood, therefore, that the term does not preclude the likelihood that one or more other features, numbers, steps, operations, ingredients, components, or combinations thereof will exist and be added.

In addition, the terms first, second, etc. are used to describe various components, but are not intended to limit the meaning of the components in any way. These terms are only used to distinguish one element from another.

Also, as used throughout the specification, the term "unit," "module," or the like denotes a single component that performs at least one function or operation and may be implemented in hardware, software, or a combination of both.

Furthermore, the control logic of the present disclosure may be embodied as non-transitory computer-readable media on a computer-readable medium containing executable program instructions that are executed by a processor, controller, or the like. Examples of computer-readable media include but are not limited to ROM, RAM, compact disc (CD)-ROMs, magnetic tape, floppy disks, flash drives, smart cards, and optical data storage devices. The computer-readable medium may also be distributed in network-coupled computer systems such that the computer-readable media are stored and executed in a distributed manner, e.g., by a telematics server or a controller area network (CAN).

It is understood that the term "vehicle" or "vehicle-related" or other similar term, as used herein, includes motor vehicles in general, such as passenger cars including SUVs (Sports Utility Vehicles (SUVs)), buses, trucks, various commercial vehicles , marine vehicles including a range of boats and ships, aircraft and the like, as well as hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen powered vehicles and vehicles using other alternative fuels (e.g. fuels derived from resources other than petroleum). As used herein, a Hybrid vehicle A vehicle that has two or more sources of energy, such as vehicles that run on both gasoline and electricity.

The same components are given the same reference numbers and redundant descriptions of the same are avoided. In this way, the preferred embodiment of the present disclosure will be described with reference to the accompanying drawings. A detailed description of a technology known in the related technical field will be omitted if it is determined that it obscures the gist of the present disclosure.

Key terms used to describe a preferred embodiment of the present disclosure have the following meanings.

The term “expected rotation speed of a turbine wheel”, one of the terms used to describe the embodiment of the present disclosure, means a value obtained by measuring a rotation speed of a drive shaft of a transmission directly connected to the turbine wheel as anticipated speed value of a torque converter turbine wheel arranged between an engine and a transmission is assumed. This value can be derived from a simple equation in which an actual rotational speed of an output shaft of the transmission (vehicle speed) is multiplied by the reciprocal of a gear ratio of a target gear shift stage.

The term “allowable speed of the turbine wheel”, one of the terms used to describe the embodiment of the present disclosure, means an allowable speed of the input shaft of the transmission. The allowable rotation speed of the turbine wheel indicates a maximum value of a rotation speed of the input shaft of the transmission at which the driving force of an engine can be stably output by gear shifting without sacrificing a load at each gear shift stage. The allowable rotation speed of the turbine wheel is a fixed value to be set in a recording device such as a memory so as to change with the gear shift stage (because a gear ratio changes with the gear shift stage).

First, an arrangement of a gear shift control system responsive to a change in a driving mode according to an embodiment of the present disclosure will be described with reference to the accompanying drawings.

1 12 is a schematic view illustrating an embodiment of an automatic transmission vehicle having the gear shift control system responsive to the change of the driving mode according to the embodiment of the present disclosure.

With reference to 1 has a gear shift control system 1 responsive to the change in driving mode according to the embodiment of the present disclosure, a mode change switch 10 for changing the driving mode, and an accelerator position sensor (APS) 20 that detects the operation of an accelerator pedal by a Driver detected and outputs a corresponding signal. In addition, the gear shift control system 1 includes a vehicle speed detector 30 which detects the rotational speed of the output shaft of the transmission, that is, the vehicle speed, and a transmission control unit (TCU) 40 .

The mode change switch 10 may preferably be mounted near a driver's seat and configured to select a desired driving mode, such as an ECO mode or a normal mode or a comfort mode or a sport mode, via a push button or rotary knob input method. The transmission control unit 40 controls a transmission based on information supplied from the mode change switch 10, the APS 20 and the vehicle speed detector 30. FIG.

Specifically, according to the embodiment, when the shift of the driving mode to the sport mode is detected while driving in a driving mode other than the sport mode, for example, the ECO mode, the normal mode, or the comfort mode, the transmission control unit 40 performs a downshift to low gear shift stage which is one stage lower than a setting gear shift stage determined by a sports mode gear shift pattern (sport mode gear shift map) according to a current output signal of the APS and a current vehicle speed. Thus, the driver can enjoy more dynamic driving and feel increased vehicle responsiveness.

To this end, the transmission control unit 40 used in accordance with the present disclosure includes multiple processors. The multiple Processors are programmed to stage a control sequence. When the change of the driving mode to the sport mode is detected while driving in a driving mode other than the sport mode, the command sequence is executed so that the forced downshift is performed to a low gear shift step that is one step lower than that over the gear shift pattern assigned to the sport mode certain setting gear shift step.

The multiple processors contained in the transmission control unit 40 and programmed to execute the control sequence in stages include a gear shift mode change detection unit 400 and a unit 410 for determining a number of low gear shift steps. In addition, the plurality of processors includes an expected turbine speed calculation unit 420 , a target gear shift step determination unit 430 , and a transmission controller 440 . In addition, the plurality of processors may further include a timing comparison unit 450 and a gear shift prohibition request unit 460 .

The gear shift mode change detection unit 400 receives information about a driving mode change from the mode change switch 10 and retrieves a gear shift pattern that matches a driving mode to which a change is made. Then, when the gear shift mode change detecting unit 400 detects a change of the driving mode to the sport mode while driving, the low gear shift number determining unit 410 determines a maximum allowable low gear shift number according to a result of determining a state of the transmission based on information about the Accelerator pedal actuation (a signal from the APS 20).

Specifically, determined at a time when a request to change the driving mode to the sport mode is recognized when an output signal of the APS 20 is equal to or more than a setting value (when the condition that the output signal of the APS 20 ≥ the setting value is satisfied , that is, when entering a state in which an accelerator pedal is operated), the low-gearshift stage number determination unit 410 determines that the transmission is in an on-state. Then, the number of lower gear shift steps that are lower than the set gear shift step determined via the gear shift pattern associated with the sport mode is determined as the maximum number of lower gear shift steps allowed.

If, for example, in a condition where the transmission is engaged and the output of the APS 20 responsive to the accelerator pedal application is thus at or above the set value, the set gear shift stage, which is determined by the gear shift pattern associated with the sport mode, to the time when the request to change the driving mode to the sport mode is the fifth level, the total number of lower gear shift levels lower than the fifth level is 4 (the fourth level, the third level, the second stage and the first stage). Therefore, in this case, the low-gear-shift-stage determining unit 410 determines that the maximum allowable low-gear-stage number is set to 4, and thus sets all gear-shift stages lower than the fifth stage to be included in a target gear-shift stage list are included.

Conversely, in a case where the output of the APS 20 at the time when the request for changing the running mode to the sport mode is detected is below the setting value, the low gear shift number determining unit 410 determines that the Transmission is in an off state. At the same time, the low-gear-step number determining unit 410 determines that the maximum allowable low-gear-gear step number is set to 1, in such a way that downshifting is allowed only to the gear-gear step (a setting gear-step number minus 1) that is one level is lower than the set gearshift level determined by the gearshift pattern associated with the sport mode.

If, for example, in a condition where the transmission is switched off and therefore the output of the APS 20, which is responsive to the application of the accelerator pedal, is below the setting value, the setting gear shift stage determined via the gear shift pattern assigned to the sport mode is the fifth stage, such as in the above example, at the time the request for switching to the sport mode is detected, the maximum number of allowable low gear shift stages is 1. Therefore, the downshift to the fourth stage becomes one stage lower than the fifth stage is set to allowed. Downshifting the gear to the gear level below, i.e. to the third or lower gear level, is determined to be impermissible. This information on the maximum number of allowable low gear shift steps is provided to the unit 420 for calculating the expected speed of the turbine wheel. The expected turbine speed calculation unit 420 calculates one immediately after the gear change expected turbine wheel speed (the speed of the input shaft of the transmission) for each step included in the maximum number of allowable low gear shift steps based on the supplied information (the information on the maximum allowable low gear shift number) based on a current speed of the output shaft of the transmission and a gear ratio of each stage.

Preferably, as described above, the immediately post-gear change speed of the turbine wheel for each stage is derived by a simple calculation in which the actual speed of the transmission output shaft (vehicle speed) is multiplied by the reciprocal of the gear ratio of each stage set in the maximum number of permitted low gear shift steps. That is, the speed of the turbine wheel expected immediately after the gear change is at a value (the current speed of the transmission output shaft/the gear ratio of each stage) resulting from the current speed of the transmission output shaft (the vehicle speed) being divided by the Transmission ratio of each stage is divided.

Information on the expected immediately after the gear change speed of the turbine wheel for each stage included in the maximum number of allowable low gear shift stages is provided to the target gear shift stage determining unit 430 . The target gear shift stage determining unit 430 compares the calculated expected turbine speed for each stage included in the maximum number of allowable low gear shift stages and a preset allowable turbine speed for each stage. The target gear shift stage determining unit 430 sets the lowest gear shift stage among gear shift stages that satisfy a predetermined condition as a final target gear shift stage.

The predetermined condition may be a condition that the speed of the turbine wheel expected immediately after the gear change for each stage does not exceed the corresponding permissible speed of the turbine wheel for each stage. As described above, the allowable rotation speed of the turbine wheel refers to a maximum value of a rotation speed of the turbine wheel at which the driving force of the engine can be stably output by gear shifting without sacrificing load capacity. Therefore, when the turbine speed immediately after the gear change (downshift) to a low gear stage is performed is higher than the corresponding allowable turbine speed, a heavy load is applied to the transmission.

2 is a table necessary for describing a process of setting a target gear shift stage. In 2 shows an example in which, in a state where the transmission is on (the output of the APS 20 ≥ the setting value), the setting gear shift stage determined by the gear shift pattern assigned to the sport mode at the time when the request for change the driving mode is detected in the sport mode and at which the current speed of the output shaft of the transmission is 2000 min ^-1 , the fifth stage.

As in 2 can be seen, in the state where the transmission is on (the output of the APS 20 ≥ the setting value), the setting gear shift step determined by the gear shift pattern assigned to the sport mode at the time when the request to change the driving mode to the sport mode is detected, the fifth stage, then when the target gear shift stage is set, the target gear shift stage determination unit 430 gives the highest priority to the first stage, which is the lowest gear shift stage among the low gear shift stages below the fifth stage. However, if the current speed of the output shaft of the gearbox is used as a reference, the first stage does not meet the above condition, since the expected speed of the turbine wheel exceeds the permissible speed of the turbine wheel.

In contrast, the second stage, which is immediately above the first stage, satisfies the condition that the expected turbine speed does not exceed the allowable turbine speed (the expected turbine speed < the allowable turbine speed). Therefore, in this case, the target gear shift stage determination unit 430 excludes the first stage as the lowest gear stage that does not satisfy the above condition from the setting of the target gear shift stage, and sets the second stage, which is among gear shift stages that satisfy the above condition, the lowest gearshift stage is fixed as the final target gearshift stage.

When the final target gearshift stage is determined through this process, the transmission controller 440 executes gearshift control to downshift the gearshift stage to the final target gearshift stage. For example, in the case of the situation in 2 the gear shift control (controls a corresponding gear shift actuator), to change the gear shift stage from the fifth stage to the second stage.

While the transmission controller 440 is performing the gear shift control, the timing comparison unit 450 performs the following operation: counting the time (a gear shift timing) required for the gear shift controller to downshift a current gear shift stage to the target gear shift stage (e.g., downshifting from the fifth stage to the second stage), and comparing the counted gear shift timing with a preset set gear shift timing.

In a case where the gearshift timing (the time required to downshift a current gearshift stage to the target gearshift stage) reaches the setting gearshift timing, which is at a setting input value, but the gearshift control is not yet completed, the timing comparison unit 450 determines that an appropriate gear shift time is exceeded, and requests the transmission controller 440 to prohibit the gear shift control.

When the forced downshift is completed by the above-described processing sequence along with a shift to the sport mode, it is necessary to maintain such a downshifted state for a predetermined time in order for the driver to experience a sufficient sense of acceleration. For this purpose, a request is made from the gear shift prohibition request unit 460 to the transmission controller 440 to prohibit the gear shift to the high gear stage to restrict the upshift after the gear shift is completed.

In the following, a process for controlling the gear change in response to the change of the driving mode will be described in detail in order to provide an understanding of the request for prohibiting the gear change to the high gear shift stage and the cancellation of the request thereof, which are performed in cooperation with the gear shift prohibition request unit 460 and of the transmission control device 440 are carried out.

3 FIG. 14 is a flowchart sequentially illustrating gear shift control processes in an order executed by the gear shift control system in FIG 1 be performed.

With reference to 3 the method for controlling a gear change in response to a change in a driving mode according to an embodiment of the present disclosure is a method for controlling a transmission in a case where switching from a driving mode other than a sport mode to the Sport mode takes place. The method starts with step S100 of determining a maximum number of allowable low gear shift stages according to a result of determining a state of a transmission based on information about an accelerator pedal operation (a signal of an APS) when a request for a change of the gear is made during driving driving mode is detected in the sport mode.

Specifically, in step S100, when an output signal of the APS at a timing when the drive mode change request is detected (in a state where an accelerator pedal is kept depressed at a preset level or more) becomes at or above a Set value is determined that the transmission is in an engaged state. Then, the number of low gear shift steps lower than a current gear shift step set according to a gear shift pattern associated with the sport mode is determined as the maximum number of low gear shift steps allowed.

If, for example, in a state in which the transmission is switched on and the output signal of the APS, which is responsive to the accelerator pedal operation, is thus at or above the set value, a set gear shift stage, which is determined via a gear shift pattern associated with the sport mode, at the time , at which the request to change the driving mode to the sport mode is the fifth level, the total number of lower gear shift levels lower than the fifth level is 4 (the fourth level, the third level, the second level and the first stage). Therefore, in this case, the maximum number of allowable low gearshift stages is set to 4, and thus all gearshift stages lower than the fifth stage are set to be included in a target gearshift stage list.

Conversely, when the output of the APS is below the set value (in a state where the accelerator pedal is kept depressed or kept depressed to less than the set value), it is determined that the transmission is in a cut-off state. Then, the maximum number of allowable low gear shift steps is determined as 1, such that downshifting is allowed only up to a gear shift step (a number of the set gear shift steps minus 1) that is one step lower than the set gear shift step, which is determined via the gear shift pattern assigned to the sport mode.

If, for example, in a condition in which the transmission is switched off and therefore the output of the APS, which is responsive to the depression of the accelerator pedal, is below the setting value, the setting gear shift stage determined by the gear shift pattern assigned to the sport mode at the time when the When a request for changing the driving mode to the sport mode is detected, which is the fifth step, the maximum number of low gear shift steps allowed is 1. Thus, downshifting to the fourth step, which is one step lower than the fifth step, is set to allowed. Downshifting to the gear ratio below, that is, to the third or lower gear ratio, is set to restricted.

If the maximum number of allowable low gear shift stages is determined by step S100, step S200 is then performed. In step S200, the expected rotation speed of the turbine for each stage included in the maximum number of allowable low gear shift stages is calculated using a current rotation speed of an output shaft of the transmission and a gear ratio of each stage, and the calculated expected rotation speed of the turbine wheel (an expected rotation speed an input shaft of the transmission) is compared to a preset permissible speed of the turbine wheel for each stage.

Preferably, in step S200, the expected immediately after the gear shift speed of the turbine wheel for each stage is derived through a simple calculation in which an actual speed of the output shaft of the transmission (a vehicle speed) is multiplied by the reciprocal of the gear ratio of each stage that is in the maximum Number of allowable low gear shift steps is included. That is, the speed of the turbine wheel expected immediately after the gear change is at a value (the current speed of the transmission output shaft/the gear ratio of each stage) obtained by dividing the current speed of the transmission output shaft (the vehicle speed) by the gear ratio each level results.

Subsequently, step S300 is performed when the expected turbine wheel speed for each stage included in the maximum number of allowable low gear shift stages is derived from the current speed of the transmission output shaft (vehicle speed). In step S300, among gear speeds at which the expected turbine speed and the allowable turbine speed satisfy a predetermined condition, the lowest speed within the maximum allowable low speed is set as the target speed. The predetermined condition is a condition that the expected speed of the turbine wheel does not exceed the permissible speed of the turbine wheel.

Finally, when the target gearshift stage is determined by step S300, step S400 is executed to execute the gearshift control for downshifting the gearshift stage to the target gearshift stage. Subsequently, in step S500, the time (a gearshift timing) required by the gearshift controller to shift the current gearshift stage to the target gearshift stage is compared with a preset set gearshift timing.

Specifically, in step S500, while the above-described transmission controller is performing the gear shift control, the following operation is performed: counting the time (gear shift timing) required by the gear shift controller to downshift a gear stage to the target gear stage (e.g., downshifting from the fifth stage to the second stage), and comparing the counted gear shift control time with the preset set gear shift control time.

In a case where the gearshift timing (the time it takes to downshift a gearshift stage to the target gearshift stage) reaches the setting gearshift timing, which is a setting input value, but the gearshift control is not yet completed, a corresponding , set gear shift time exceeded. Therefore, in such a state, the process is ended without further executing the gear shift control. When the set gearshift timing is not exceeded, whether or not the gearshift is completed is monitored based on the target gearshift stage (S510).

At this point, in a case where the gearshift timing is equal to or shorter than the set gearshift timing and the gear change to the target gearshift stage has not been completed, the process can be set to return to step S400 and step S400 and subsequent steps are repeatedly performed.

When the forced downshift is completed by the above-described processing sequence along with a shift to the sport mode, it is necessary to maintain such a downshifted state for a predetermined time in order for a driver to experience a sufficient sense of acceleration. For this purpose, a controller for completing the gear change and at the same time for restricting the gear change to the high gear stage (S600). Preferably, the upshift restraining control is executed until a predetermined required condition described below is satisfied.

The upshift restriction control is described in more detail below.

4 Fig. 14 is a flowchart for the high-speed upshift prohibition control, the control being performed immediately after the downshift is performed in response to the change of the running mode to the sport mode during running.

With reference to 4 step S600 generally includes step S610 and step S620. In step S610, a gear shift prohibition request is made to restrict the gear shift toward the high gear stage after the gear shift is completed. In step S620, after gear shifting is completed, a current gear shift stage (the gear shift stage corresponding to the target gear shift stage) is compared with the setting gear shift stage, which is determined via the gear shift pattern assigned to the sport mode according to a current output signal of the APS and the vehicle speed, and accordingly As a result of the comparison, it is determined whether the prohibition of gear shifting to the high gear stage is released or maintained.

Specifically, as a result of the comparison by step S620, when a current gear shift stage is equal to the setting gear stage or is the high gear stage, the gear shift prohibition control to the high gear stage is necessary (S622). When the current gear shift stage is the gear stage lower than the setting gear stage, by maintaining the prohibition of gear shifting to the high gear stage and using additional information, a timing when the prohibition of gear shifting to the high gear stage is released ( S624).

Upon entering step S624, a current engine speed is first compared to a preset allowable engine speed to prevent engine overrun (S6240). As a result, if the current engine speed is higher than the allowable engine speed, a forced gear shift to a high gear stage that is one stage higher than the current gear stage (the gear stage corresponding to the target gear stage) is performed (S6241). Then, the resultant high gear shift stage is compared with the set gear stage determined by the gear shift pattern assigned to the sport mode according to the output signal of the APS and the vehicle speed (S6246).

As a result (a result of the comparison via step S6246), if the high gearshift stage which is one stage higher is equal to or higher than the set gearshift stage, the prohibition of gearshifting to the high gearshift stage is immediately canceled (S6247). If the high gear shift stage that is one stage higher is the low gear stage that is still lower than the setting gear stage, the forced gear shifting to a gear stage that is one stage higher is further performed (S6248). Then, there is a return to step S6246, in which the resultant high gear shift stage is compared with the set gear stage, and then step S6246 and subsequent steps are repeatedly performed.

Conversely, if the result of the comparison via step S6240 is that the current engine speed is lower than the allowable engine speed, it is determined based on the output of the APS and information about the time that its output continues to be provided the driver intends to experience acceleration or not (S6242). Preferably, in step S6242, it is determined if the output signal of the APS continues to be provided in a state at or above the setpoint (the setpoint used to determine whether the transmission is engaged or not) for a preset time or longer that the driver actually intends to experience acceleration.

When it is determined in step S6242 that the driver actually intends to experience acceleration (when the output of the APS remains in the state of being at or above the set value (the set value used for the preset time). is to determine whether or not the transmission is on), a timer (a timer for detecting acceleration) is operated (S6243), and at the same time, an increase in vehicle speed obtained after a point of time when the gear change into a current gearshift step is compared with a preset reference value for vehicle speed increase (S6244).

At this point, if the vehicle speed increase is at or above the vehicle speed increase reference value, then this situation is recognized as an increase in vehicle speed due to a road gradient and not as the driver's intention to experience acceleration. Therefore, the process immediately jumps to step S6241. When the vehicle speed increase is below the vehicle speed increase reference value, a value of the time for which the timer is operated is compared with a preset time reference value (S6245). Then, at a point of time when the value of the time is higher than the preset time reference value, the process shifts to step S6241 described above.

In the related art, in a case of switching from a driving mode other than the sport mode to the sport mode while driving, the gear change is uniformly performed in accordance with a gear shift reference point set in the gear shift pattern assigned to the sport mode according to a current vehicle condition (the vehicle speed and an amount of work on a pedal). Thus, there is a disadvantage that the driver's desire to enjoy dynamic driving is not satisfied.

In contrast, according to the embodiment of the present disclosure, when switching from a driving mode other than the sport mode to the sport mode during driving, the target gear shift stage is set to be a low stage lower than the gear shift stage, that is set in the gear shift pattern (a gear shift map) associated with the sport mode (gear shifting up to the lowest gear shift stage is permitted based on the allowable rotation speed of the turbine wheel for each stage). Accordingly, downshifting is performed in a wider range. Thus, the driver's desire to enjoy dynamic driving can be met.

Only the preferred embodiment of the present disclosure is described above. However, the present disclosure should not be construed as limited to the preferred embodiment. Any changes, equivalents, or substitutions that do not depart from the gist of the present disclosure should be understood to fall within the scope of the present disclosure, which is defined in the claims below.

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• KR 1020210047283 [0001]

Claims (19)

A method for controlling a gear shift in response to a change in driving mode, the method comprising: (a) Determining a maximum number of allowable low gear shift stages according to a result of determination of a state of a transmission based on information about an accelerator pedal operation (a signal from an accelerator pedal position sensor (APS)) when a request for a change of a driving mode into a Sport mode is detected (b) Calculating an immediately after gear change expected speed of a turbine wheel for each stage included in the maximum number of allowable low gear shift stages using a current speed of an output shaft of the transmission and a gear ratio of each stage and comparing the calculated expected speed of the turbine wheel (a speed of an input shaft of the transmission) with a preset allowable speed of the turbine wheel for each stage, (c) setting the lowest gear ratio from gear ratios at which the expected turbine speed and the allowable turbine speed meet a predetermined condition such that it is a target gear ratio within the maximum number of allowable low gear ratios, and (d) executing gear shift control to downshift a current gear shift stage to the target gear shift stage. procedure after claim 1 wherein in (a) determining the maximum number of allowable low gear shift steps, if an output signal of an APS is at or above a set value at a time when the request to change the driving mode is detected, it is determined that the transmission is in an on state, and if the output of the APS is below the set value, it is determined that the transmission is in an off state. procedure after claim 2 , wherein when the transmission is in the engaged state, the number of low gear ratios lower than a setting gear ratio determined via a gear shift pattern associated with a sport mode is determined as the maximum number of low gear ratios allowed, and if the transmission is in the off state, the maximum number of allowable low gear ratios is determined as 1, such that low gear shifting is only permitted to a low gear ratio (a set gear ratio number minus 1) that is one ratio lower than the setting Gear shift step, which is determined via the gear shift pattern assigned to the sport mode. Method according to any one of the preceding claims, wherein in (b) the calculation of the expected immediately after the gear change speed of the turbine wheel, the speed of the turbine wheel expected immediately after the gear change for each stage at a value (the current speed of the output shaft of the transmission / the gear ratio of each stage) that results from dividing the current speed of the transmission output shaft by the gear ratio of each stage. The method of any preceding claim, wherein in (c) setting the lowest gear ratio, the predetermined condition is that the expected turbine speed does not exceed the allowable turbine speed. A method according to any one of the preceding claims, further comprising: comparing the time (a gearshift timing) required for the gearshift controller to downshift the current gearshift stage to the target gearshift stage at (d) the execution of the gearshift control with a preset set gearshift timing, when the gearshift timing exceeds the set gearshift timing, a process in such a state is terminated without further executing the gearshift control, and when the gearshift timing is shorter than the set gearshift timing, it is determined whether or not the gearshift to the target gearshift stage is completed, and if the gearshift is completed within the set gearshift timing, the process is ended. procedure after claim 6 , wherein in a case where the gearshift timing is shorter than the set gearshift timing and the gear change to the target gearshift stage is not completed, returning to (d) the execution of the gearshift control and (d) the execution of the gearshift control, and ( e) the comparison of the time required for the gear shift control can be carried out repeatedly. procedure after claim 6 or 7 1 . further comprising: (f) executing control to restrict gear shifting to a high gear shift stage toward after gear shifting to the target gear shift stage is completed. procedure after claim 8 wherein (f) executing the gear shift restriction control comprises: (f-1) making a gear shift prohibition request to the high gear shift stage to restrict the gear shift to the high gear shift stage after the gear shift to the target gear shift is completed, and (f-2) comparing the current gearshift stage (a gearshift stage corresponding to the target gearshift stage) with a set gearshift stage determined by a gearshift pattern assigned to a sport mode, according to a current output signal of the APS and a current vehicle speed , and determining, depending on a result of the comparison, whether prohibition of gear shifting to the high gear shift stage is released or maintained. procedure after claim 9 wherein (f-2) comparing the current gearshift stage with the setting gearshift stage comprises: (f-2-1) immediately releasing the prohibition of the gearshift to the high gearshift stage because the control for prohibiting the gearshift to the high gearshift stage is unnecessary is when the current gearshift stage (the gearshift stage corresponding to the target gearshift stage) is equal to the setting gearshift stage or is the high gearshift stage, and (f-2-2) maintaining the prohibition of gearshifting to the high gearshift stage when the current gear shift stage (the gear shift stage corresponding to the target gear stage) is a lower gear stage than the set gear stage, and determining a timing at which the prohibition of gear shifting to the high gear stage is released by using additional information. procedure after claim 10 , wherein in (f-2-2) maintaining the gear shift prohibition comparing a current engine speed with a preset allowable engine speed to prevent engine overrun, then if the current engine speed is higher than the allowable engine speed, a forced gear shift on a high gear shift step which is one step higher than the current gear shift step (the gear shift step corresponding to the target gear shift step), and then the resulting high gear shift step is compared with the set gear shift step corresponding to the gear shift pattern assigned to the sport mode the current output signal of the APS and the current vehicle speed, and when the high gear shift step higher by one step is higher than the set gear shift step, the prohibition of gear shifting to the high gear shift step is released. procedure after claim 11 , wherein when the current engine speed is lower than the permissible engine speed, it is determined whether or not a driver intends to experience acceleration based on an output signal of the APS and the time that the output signal thereof continues to be provided , wherein if the output of the APS continues to be provided in a state where it is at or above the set value for a set time or longer, it is determined that the driver actually intends to experience acceleration, so that a timer is actuated and, at the same time, an increase in vehicle speed obtained after a point in time when gear shifting to the current gear stage is completed is compared with a preset reference value for the increase in vehicle speed, and when the increase in vehicle speed is at or above the reference value for the increase in vehicle speed, this situation is recognized as an increase in vehicle speed due to a downgrade of a road and not as an intention to experience acceleration, and thus the forced gear shifting to a high gear shift step which is one step higher than the current gear shift step (the target -gearshift stage) is performed immediately, and thereafter comparing the resulting high gearshift stage with the set gearshift stage determined via the gearshift pattern associated with the sport mode according to the current output signal of the APS and the current vehicle speed, and if the high gear shift step one step higher than the setting gear shift step, the prohibition of gear shifting to the high gear shift step is released. procedure after claim 12 wherein as a result of comparing the vehicle speed increase obtained after the time point at which gear shifting is completed with the vehicle speed increase reference value when the vehicle speed increase is below the vehicle speed increase reference value , a value of the time over which the timer is operated is compared with a preset time reference value, and at a point in time when the time value is higher than the time reference value, the forced gear shift to a high gear shift stage which is one stage higher than the current gear shift stage is performed, and thereafter comparing the resultant high gear shift stage with the set gear stage determined by the gear shift pattern associated with the sport mode according to the current output signal of the APS and the current vehicle speed, and then if the high gear stage, which is one stage higher than the set gearshift stage, the prohibition of gearshifting to the high gearshift stage is released. Procedure according to one of Claims 11 until 13 , wherein the forced gear shifting to a high gear stage which is one stage higher than the current gear stage (the gear stage corresponding to the target gear stage) is performed, and then the resulting high gear stage is compared with the setting gear stage which is above the gear shift pattern assigned to the sport mode is determined according to the current output signal of the APS and the current vehicle speed, and as a result of the comparison, when the high gear shift step which is one step higher is lower than the setting gear shift step, a forced gear shift to a high one gear shift stage higher by one stage is performed, and thereafter returning to comparing the resultant high gear shift stage with the set gear shift stage and comparing the resultant high gear shift stage and a subsequent operation are repeatedly performed. A system for controlling a gear change in response to a change in driving mode, the system comprising: a mode change switch for changing a driving mode, an accelerator pedal position sensor (APS), which is set up in such a way that it detects the actuation of an accelerator pedal by a driver and outputs a corresponding signal, a vehicle speed detector arranged to detect a rotational speed of an output shaft of a transmission, and a transmission control unit (TCU) arranged to control the transmission based on information provided by the mode change switch, the APS and the vehicle speed detector, wherein when a change from a driving mode other than a sport mode to the sport mode is detected during driving, the transmission control unit executes a downshift control to a low gear shift step that is one step lower than a setting gear shift step that is above a sport mode associated gear shift pattern is determined. system after claim 15 wherein the transmission control unit comprises: a gearshift mode change detection unit arranged to receive information about a driving mode change from the mode change switch and retrieve a gearshift pattern that matches a driving mode to which a change occurs, a unit for determining a number of low gearshift steps , which is arranged to determine a maximum number of allowable low gear shift stages according to a result of determining a state of the transmission based on information about an accelerator pedal operation (a signal of an APS) when the gear shift mode change detection unit changes the driving mode to the sport mode during of driving, an expected turbine speed calculation unit configured to calculate an expected turbine speed immediately after the gear shift (a drive train speed lle of the transmission) calculated for each stage included in the maximum number of allowable low gear shift stages, using a current speed of an output shaft of the transmission and a gear ratio of each stage, a target gear shift stage determination unit, which is set up to determine the lowest gear shift stage gear shift stages at which the calculated expected turbine wheel speed for each stage included within the maximum number of allowable low gear shift stages and a preset allowable turbine wheel speed for each stage satisfy a predetermined condition as a target gear shift stage, a transmission controller, arranged to execute gearshift control to downshift a gearshift stage to the target gearshift stage, and a gearshift prohibition request unit arranged to make a request to the transmission control unit performs a gear-shift prohibition to a high-gear-speed step to restrict the gear-shift to the high gear-speed step after the gear-shifting to the target gear-speed step is completed. system after Claim 16 wherein, when an output signal of the APS is at or above a set value at a timing when a driving mode change request is detected, the low gear shift number determining unit determines that the transmission is in an engaged state condition and determines as the maximum number of allowable low gear ratios the number of low gear ratios lower than the set gear ratio determined by the gear shift pattern associated with the sport mode, and if the output of the APS is below the set value, the unit to Determination of the number of low gear ratios determines that the transmission is in an off state and determines the maximum number of low gear ratios allowed as 1, such that a low gear shift only results in a low gear ratio (a setting gear ratio number minus 1) is enabled, which is one step lower than the setting gear shift step determined by the gear shift pattern associated with the sport mode. system after Claim 16 or 17 , wherein the predetermined condition is a condition that the expected speed of the turbine wheel does not exceed the allowable speed of the turbine wheel. system according to one of the Claims 16 until 18 wherein the transmission control unit further comprises: a timing comparison unit configured to count the time (a gearshift timing) required for the gearshift controller to downshift a current gearshift stage to the target gearshift stage, and the counted gearshift timing with a preset one To compare set gearshift timing, wherein when the gearshift timing exceeds the set gearshift timing, the timing comparison unit makes a request to the transmission controller to prevent the gearshift control.

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